A reasonably large literature has emerged over the past decade suggesting that cortisol activity early in life is socially regulated (Gunnar & Donzella, 2002). Specifically, recent evidence suggests that chronic and/or intense-acute stress during early development can result in long term changes to cortisol activity (Bremmner & Vermetten, 2001); and, an emerging literature now implicates these effects in PTSD and other psychopathology later in life (McEwen, 2000). The specific aims of this project are: 1) to estimate the relative effects of adverse early experience including child abuse/neglect, intra family conflict and income to needs on the regulation of cortisol response over the course of the morning and in response to intense peer interaction (a novel ecologically relevant stress) in at risk preschool children; 2) to model the moderating effects of childcare/school factors (quality of the care giving environment, quality of the teacher child relationship) and child factors (expressive language, social competence) on associations between risk and the regulation of cortisol response over the course of the morning and in response to intense peer interaction. Participants will consist of sixty 24-36 month old children enrolled in all day childcare. [unreadable] [unreadable]